Sustaining Long-Term Asthma Outcomes at a Community and Tertiary Care Pediatric Hospital.

BACKGROUND AND OBJECTIVES: Implementing asthma Clinical Practice Guidelines (CPG) have been shown to improve length of stay (LOS) and readmission rates on a short-term basis at both tertiary care and community hospital settings. Whether these outcomes are sustained long term is not known. The goal of this study was to measure the long-term impact of CPG implementation at both tertiary and community sites in 1 hospital system. METHODS: A retrospective study was conducted using the Pediatric Health Information System database. LOS and 7- and 14-day emergency department (ED) revisit and readmission rates from 2009 to 2020 were compared pre and post implementation of asthma CPG in 2012 at both sites. Implementation involved electronic order sets, early metered dose inhaler introduction, and empowering respiratory therapists to wean per the bronchodilator weaning protocol. Interrupted time series and statistical process control charts were used to assess CPG impact. RESULTS: Implementation of asthma CPG was associated with significant reductions in the variability of LOS without impacting ED revisit or readmission rates at both the tertiary and community sites. Secular trends in the interrupted time series did not demonstrate significant impact of CPG on LOS. However, the overall trend toward decreased LOS that started before CPG implementation was sustained for 7 years after CPG implementation. CONCLUSIONS: Early metered dose inhaler introduction, respiratory therapist-driven bronchodilator weaning, and electronic order sets at both the community and tertiary care site led to a significant reduction in the variation of LOS, without impacting ED revisit or readmission rate.

Altered receptor trafficking in Huntingtin Interacting Protein 1-transformed cells.

The clathrin-associated protein, Huntingtin Interacting Protein 1 (HIP1), is overexpressed in multiple human epithelial tumors. Here, we report that HIP1 is a novel oncoprotein that transforms cells. HIP1-transformed cells, in contrast to RasV12-transformed cells, have dysregulation of multiple receptors involved in clathrin trafficking. Examples include upregulation of the epidermal growth factor receptor (EGFR) and the transferrin receptor. Furthermore, accumulation of transferrin and EGF in the HIP1-transformed cells was increased, and breast tumors that had EGFR expressed also had HIP1 upregulated. Thus, HIP1 overexpression promotes tumor formation and is associated with a general alteration in receptor trafficking. HIP1 is the first endocytic protein to be directly implicated in tumor formation.

Huntingtin interacting protein 1 is a novel brain tumor marker that associates with epidermal growth factor receptor.

Huntingtin interacting protein 1 (HIP1) is a multidomain oncoprotein whose expression correlates with increased epidermal growth factor receptor (EGFR) levels in certain tumors. For example, HIP1-transformed fibroblasts and HIP1-positive breast cancers have elevated EGFR protein levels. The combined association of HIP1 with huntingtin, the protein that is mutated in Huntington's disease, and the known overexpression of EGFR in glial brain tumors prompted us to explore HIP1 expression in a group of patients with different types of brain cancer. We report here that HIP1 is overexpressed with high frequency in brain cancers and that this overexpression correlates with EGFR and platelet-derived growth factor beta receptor expression. Furthermore, serum samples from patients with brain cancer contained anti-HIP1 antibodies more frequently than age-matched brain cancer-free controls. Finally, we report that HIP1 physically associates with EGFR and that this association is independent of the lipid, clathrin, and actin interacting domains of HIP1. These findings suggest that HIP1 may up-regulate or maintain EGFR overexpression in primary brain tumors by directly interacting with the receptor. This novel HIP1-EGFR interaction may work with or independent of HIP1 modulation of EGFR degradation via clathrin-mediated membrane trafficking pathways. Further investigation of HIP1 function in brain cancer biology and validation of its use as a prognostic or predictive brain tumor marker are now warranted.

Aberrant Huntingtin interacting protein 1 in lymphoid malignancies.

Huntingtin interacting protein 1 (HIP1) is an inositol lipid, clathrin, and actin binding protein that is overexpressed in a variety of epithelial malignancies. Here, we report for the first time that HIP1 is elevated in non-Hodgkin's and Hodgkin's lymphomas and that patients with lymphoid malignancies frequently had anti-HIP1 antibodies in their serum. Moreover, p53-deficient mice with B-cell lymphomas were 13 times more likely to have anti-HIP1 antibodies in their serum than control mice. Furthermore, transgenic overexpression of HIP1 was associated with the development of lymphoid neoplasms. The HIP1 protein was induced by activation of the nuclear factor-kappaB pathway, which is frequently activated in lymphoid malignancies. These data identify HIP1 as a new marker of lymphoid malignancies that contributes to the transformation of lymphoid cells in vivo.

Hip1-related mutant mice grow and develop normally but have accelerated spinal abnormalities and dwarfism in the absence of HIP1.

In mice and humans, there are two known members of the Huntingtin interacting protein 1 (HIP1) family, HIP1 and HIP1-related (HIP1r). Based on structural and functional data, these proteins participate in the clathrin trafficking network. The inactivation of Hip1 in mice leads to spinal, hematopoietic, and testicular defects. To investigate the biological function of HIP1r, we generated a Hip1r mutant allele in mice. Hip1r homozygous mutant mice are viable and fertile without obvious morphological abnormalities. In addition, embryonic fibroblasts derived from these mice do not have gross abnormalities in survival, proliferation, or clathrin trafficking pathways. Altogether, this demonstrates that HIP1r is not necessary for normal development of the embryo or for normal adulthood and suggests that HIP1 or other functionally related members of the clathrin trafficking network can compensate for HIP1r absence. To test the latter, we generated mice deficient in both HIP1 and HIP1r. These mice have accelerated development of abnormalities seen in Hip1 -deficient mice, including kypholordosis and growth defects. The severity of the Hip1r/Hip1 double-knockout phenotype compared to the Hip1 knockout indicates that HIP1r partially compensates for HIP1 function in the absence of HIP1 expression, providing strong evidence that HIP1 and HIP1r have overlapping roles in vivo.

Serum antibodies to huntingtin interacting protein-1: a new blood test for prostate cancer.

Huntingtin-interacting protein 1 (HIP1) is frequently overexpressed in prostate cancer. HIP1 is a clathrin-binding protein involved in growth factor receptor trafficking that transforms fibroblasts by prolonging the half-life of growth factor receptors. In addition to human cancers, HIP1 is also overexpressed in prostate tumors from the transgenic adenocarcinoma of the mouse prostate (TRAMP) mouse model. Here we provide evidence that HIP1 plays an important role in mouse tumor development, as tumor formation in the TRAMP mice was impaired in the Hip1null/null background. In addition, we report that autoantibodies to HIP1 developed in the sera of TRAMP mice with prostate cancer as well as in the sera from human prostate cancer patients. This led to the development of an anti-HIP1 serum test in humans that had a similar sensitivity and specificity to the anti-alpha-methylacyl CoA racemase (AMACR) and prostate-specific antigen tests for prostate cancer and when combined with the anti-AMACR test yielded a specificity of 97%. These data suggest that HIP1 plays a functional role in tumorigenesis and that a positive HIP1 autoantibody test may be an important serum marker of prostate cancer.

Use of a cryptic splice site for the expression of huntingtin interacting protein 1 in select normal and neoplastic tissues.

Huntingtin interacting protein 1 (HIP1) is a 116-kDa endocytic protein, which is necessary for the maintenance of several tissues in vivo as its deficiency leads to degenerative adult phenotypes. HIP1 deficiency also inhibits prostate tumor progression in mice. To better understand how deficiency of HIP1 leads to such phenotypes, we analyzed tumorigenic potential in mice homozygous for a Hip1 mutant allele, designated Hip1(Delta 3-5), which is predicted to result in a frame-shifted, nonsense mutation in the NH(2) terminus of HIP1. In contrast to our previous studies using the Hip1 null allele, an inhibition of tumorigenesis was not observed as a result of the homozygosity of the nonsense Delta 3-5 allele. To further examine the contrasting results from the prior Hip1 mutant mice, we cultured tumor cells from homozygous Delta 3-5 allele-bearing mice and discovered the presence of a 110-kDa form of HIP1 in tumor cells. Upon sequencing of Hip1 DNA and message from these tumors, we determined that this 110-kDa form of HIP1 is the product of splicing of a cryptic U12-type AT-AC intron. This event results in the insertion of an AG dinucleotide between exons 2 and 6 and restoration of the reading frame. Remarkably, this mutant protein retains its capacity to bind lipids, clathrin, AP2, and epidermal growth factor receptor providing a possible explanation for why tumorigenesis was not altered after this knockout mutation. Our data show how knowledge of the transcript that is produced by a knockout allele can lead to discovery of novel types of molecular compensation at the level of splicing.

Degenerative phenotypes caused by the combined deficiency of murine HIP1 and HIP1r are rescued by human HIP1.

The members of the huntingtin-interacting protein-1 (HIP1) family, HIP1 and HIP1-related (HIP1r), are multi-domain proteins that interact with inositol lipids, clathrin and actin. HIP1 is over-expressed in a variety of cancers and both HIP1 and HIP1r prolong the half-life of multiple growth factor receptors. To better understand the physiological importance of the HIP1 family in vivo, we have analyzed a large cohort of double Hip1/Hip1r knockout (DKO) mice. All DKO mice were dwarfed, afflicted with severe vertebral defects and died in early adulthood. These phenotypes were not observed during early adulthood in the single Hip1 or Hip1r knockouts, indicating that HIP1 and HIP1r compensate for one another. Despite the ability of HIP1 and HIP1r to modulate growth factor receptor levels when over-expressed, studies herein using DKO fibroblasts indicate that the HIP1 family is not necessary for endocytosis but is necessary for the maintenance of diverse adult tissues in vivo. To test if human HIP1 can function similar to mouse HIP1, transgenic mice with 'ubiquitous' expression of the human HIP1 cDNA were generated and crossed with DKO mice. Strikingly, the compound human HIP1 transgenic DKO mice were completely free from dwarfism and spinal defects. This successful rescue demonstrates that the human HIP1 protein shares some interchangeable functions with both HIP1 and HIP1r in vivo. In addition, we conclude that the degenerative phenotypes seen in the DKO mice are due mainly to HIP1 and HIP1r protein deficiency rather than altered expression of neighboring genes or disrupted intronic elements.

Estrogen receptor-positive human epithelial ovarian carcinoma cells respond to the antitumor drug suramin with increased proliferation: possible insight into ER and epidermal growth factor signaling interactions in ovarian cancer.

OBJECTIVES: Development of targeted therapeutics for ovarian cancer requires a basic understanding of ovarian epithelial carcinoma cell biology. The role of estrogen and epidermal growth factor (EGF) in control of cell growth was investigated in a panel of ovarian carcinoma lines. METHODS: EGF receptor (EGFR) was detected by flow cytometry and estrogen receptor (ER) by Northern blot. Western blotting and [(3)H]thymidine incorporation were used to determine receptor activation and the effects of ligand exposure and growth factor antagonists, including the antineoplastic agent, suramin, on cell growth. RESULTS: Only one cell line, OV266, expressed ER and responded to beta-estradiol with increases in DNA synthesis and cell proliferation that could be blocked by the pure antiestrogen ICI 182,780. All cell lines possessed functional EGFR as measured by flow cytometry and phosphorylation of the receptor and mitogen-activated protein kinase after EGF treatment, but only two cell lines (OV177 and OV266) proliferated in response to exogenous EGF. Suramin had limited effectiveness in inhibiting growth in four of five cell lines and had a striking dose-dependent stimulatory effect on OV266 cell growth. The proliferative response to suramin could be inhibited with EGFR antagonists. CONCLUSION: Cultured epithelial ovarian carcinoma cell lines express EGFR (5/5) and can express ER (1/5). Differential growth responses to EGF were observed despite uniform receptor and MAPK activation. Unexpectedly, the antineoplastic agent suramin increased growth of ER positive ovarian carcinoma cells in an EGFR-dependent manner. These studies provide insight into the complex interactions of these systems in control of ovarian cancer cell growth.

HIP1 and HIP1r stabilize receptor tyrosine kinases and bind 3-phosphoinositides via epsin N-terminal homology domains.

Huntingtin-interacting protein 1-related (HIP1r) is the only known mammalian relative of huntingtin-interacting protein 1 (HIP1), a protein that transforms fibroblasts via undefined mechanisms. Here we demonstrate that both HIP1r and HIP1 bind inositol lipids via their epsin N-terminal homology (ENTH) domains. In contrast to other ENTH domain-containing proteins, lipid binding is preferential to the 3-phosphate-containing inositol lipids, phosphatidylinositol 3,4-bisphosphate and phosphatidylinositol 3,5-bisphosphate. Furthermore, the HIP1r ENTH domain, like that of HIP1, is necessary for lipid binding, and expression of an ENTH domain-deletion mutant, HIP1r/deltaE, induces apoptosis. Consistent with the ability of HIP1r and HIP1 to affect cell survival, full-length HIP1 and HIP1r stabilize pools of growth factor receptors by prolonging their half-life following ligand-induced endocytosis. Although HIP1r and HIP1 display only a partially overlapping pattern of protein interactions, these data suggest that both proteins share a functional homology by binding 3-phosphorylated inositol lipids and stabilizing receptor tyrosine kinases in a fashion that may contribute to their ability to alter cell growth and survival.